Electrochemical chlorine absorption in cyclone membrane reactor: analysis of reaction mechanism and transport phenomena

A new reactive separation process is presented and analyzed which is based on simultaneous, dispersionless gas-liquid absorption and electrochemical r eaction in the pore structure of electrically conductive membranes. As a mo del process of technical and environmental relevance, the electrochemical a bsorption of chlorine waste gases in hydrochloric acid is studied, both exp erimentally and theoretically. The membranes were manufactured from porous carbon black particles by rolling agglomeration. The reaction mechanisms an d mass transport phenomena within these membranes were investigated in a no vel cyclone flow reactor. With this membrane reactor, a series of experimen ts was carried out under control of membrane electrode potential using chlo rine-nitrogen gas mixtures (1000 ppm Cl-2). A model-based analysis of exper imental data reveals the electrochemical reaction microkinetics to follow t he Volmer-Heyrovsky mechanism. Mass transport was found to be dominated by Knudsen diffusion in the membrane micropores. (C) 2001 Elsevier Science B.V . All rights reserved.